Therapy of chronic viral hepatitis: a critical view

Many oral nucleoside analogues that are potent inhibitors of hepatitis B virus have recently been developed for the treatment of hepatitis B. The problems with these drugs are bioavailability, toxicity and the time-dependent emergence of resistant hepatitis B virus mutants. Lamivudine appears to be the most useful in terms of clinical benefit, safety and tolerance. It is active on wild type hepatitis B virus as well as on HBeAg-minus variants of the virus. However, although hepatitis B virus is consistently repressed while on therapy, only a minority of patients are cured or remain in remission after Lamivudine withdrawal. Maintenance therapy would appear to be in order, but the long-term use of Lamivudine is precluded by the emergence of polymerase gene-mutants which may rekindle disease. Combination with other antivirals (Adefovir?) active also against Lamivudine escape mutants opens promising new prospects. There is, as yet, no valid therapy for chronic hepatitis D virus hepatitis. Attempts to improve the results of alpha-interferon therapy in chronic hepatitis C with new interferons, or the manipulation of interferon monotherapy so as to obtain the maximum results compatible with tolerance, have not produced significantly better results than the classic protocols of alpha-interferon monotherapy. A more concrete improvement has been achieved by the combination of interferon with Ribavirin, with the overall rate of response increasing three times compared to interferon monotherapy. Anaemia, however, is a common additional side-effect induced by Ribavirin. Combination therapy has become the treatment of choice for interferon naive patients as well as for interferon relapses; it is not efficacious in patients who have not responded to interferon.